FREE Ecology Biogeochemical Cycles Questions and Answers

Question 1

Which of the following processes is primarily responsible for returning carbon from the atmosphere to terrestrial biomass in the short term?

Accepted Answer

Photosynthesis

Answer

Respiration

Answer

Combustion of fossil fuels

Answer

Decomposition

Question 2

A farmer observes a decline in crop yield despite consistent watering and sunlight. Soil analysis reveals a significant depletion of nitrates. Which biogeochemical cycle is most directly impacted, and what is a likely contributing factor to this depletion?

Accepted Answer

Nitrogen cycle; lack of nitrogen-fixing bacteria

Answer

Phosphorus cycle; excessive weathering of rocks

Answer

Carbon cycle; increased atmospheric CO2

Answer

Water cycle; reduced precipitation

Question 3

Which of the following human activities significantly contributes to the acidification of oceans by increasing the absorption of carbon dioxide?

Accepted Answer

Burning of fossil fuels

Answer

Deforestation

Answer

Agricultural runoff

Answer

Overfishing

Question 4

In the global phosphorus cycle, what is the primary reservoir for phosphorus?

Accepted Answer

Sedimentary rocks

Answer

Atmosphere

Answer

Oceans (dissolved)

Answer

Living organisms

Question 5

A scientist is studying a forest ecosystem and observes that a significant amount of sulfur is being released into the atmosphere from volcanic activity. How might this directly impact the local ecosystem's biogeochemical cycles?

Accepted Answer

Contribute to acid deposition (acid rain)

Answer

Increase carbon sequestration by plants

Answer

Enhance nitrogen fixation in the soil

Answer

Accelerate the decomposition rate of organic matter

Question 6

Which statement accurately describes a key difference between the global water cycle and the global nitrogen cycle?

Accepted Answer

The water cycle is primarily driven by solar energy, while the nitrogen cycle is primarily driven by microbial activity.

Answer

The water cycle involves a gaseous atmospheric phase, while the nitrogen cycle does not.

Answer

The water cycle is a closed system, while the nitrogen cycle is an open system.

Answer

Water is a limiting nutrient in most ecosystems, but nitrogen is not.